Escapement-wheel



( No Model.)

G. s. HEATH & A. P. GHAMPLIN.

'ESOAPEM-ENT WHEEL. No. 361,945. Pa,tentedApr.-26, 1887,,

UNITED STATES PATENT OFFICE.

GEORGE S. HEATH AND AMOS F. CHAMPLIN, OF HARTFORD, CONNECTICUT.

ESCAPEMENT-WHEELE SPECIFICATION forming part of Letters Patent No. 361,945, dated April 26, 1887.

Application filed September 9, 1885. Renewed July 22, 1886. Serial No. 208.522. (No model.)

To all whom it mayconcern:

Beitknown that we, GEORGE S. HEATH and Amos F. OHAMPLIN, of Hartford, in the county of Hartford, and in the State of Connecticut,

have invented certain new and useful Improvements in Escape-Wheels for Time Mechanisms; and we do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, in which I said tooth; and Fig. 3 is a like view of an cscape-wheel tooth of usual form, with lines indicating the radial positions of the pallet-pin at the same points as in Fig. 2.

Letters of like name and kind refer to like parts in eachof the figures.

In escapements as heretofore constructed the impulse or lifting faces of the teeth of the escape-wheels have been made straight, and their action has been such as to give to the pallet-pin the same velocity from the commencement to the close of its contact with such face. As, however, the greatest power is necessary at the commencement of the motion,in order to overcome the inertia of the time-train and pallet-lever, and the greatest impulse is desirable at the moment of banking, such form of the impulse-face is incorrect and fails to secure the best results.

To overcome the defects named is the obj ect of our invention, which invention consists, principally, in an escape-wheel for time mechanism, in which the lifting or impulse face of each tooth is formed upon a rearward and outward curve, substantially as and for the purpose hereinafter specified.

It consists, further, in an escape-wheel for time mechanism, which is adapted to give to the pallet-pin a constantly-increasing velocity from the commencement to the close of its contact with each tooth, substantially as and for the purpose hereinafter shown.

In the annexed drawings, A represents our improved escape-wheel, which is provided with any desired number of peripheral teeth,

a, that have the usual form, except that the impulseface a of each is formed upon a rearward and outward curve, instead of the usual rearwardly and outwardly extending straight line, as seen in Fig. 3.

A pallet-lever, B, of ordinary form and provided with pallet-pins b, is pivoted at a suitable point to enable said pins to be engaged with the teeth a of the wheel A, and when in operation each of said pins is, by the oscillation of said lever, caused to impinge upon the front side of a tooth, so as to arrest the motion of said wheel, and then to move radially outward until said tooth is released, and said wheel is permitted to rotate forward to bring another tooth into engagement with the opposite pallet-pin, all in the usual manner.

As each pallet-pin 1) leaves the front side of a tooth, a, the forward motion of the wheel A causes the impulse-face a of said tooth to pass beneath said pin and give to the same the usual outward impulse; but instead of moving said pin outward with a uniform velocity the effect of the curvature of said impulse-face is to give to said pin but little velocity at the commencement of its contact therewith, and to constantly increase the velocity up to the point of their disengagement-the moment of banking.

In consequence of the curvature of the impulse-face a, the lifting force required is least at the commencement of the movement of the escape-wheel, when the inertia of the entire train has to be overcome, and is greatest at the close of such motion, when the momentum of said train is added to the power of the mainspring, by which means the power necessary for the moving of the train from one pointof rest to another point of rest is equalized, and the maximum of outward pressure upon the pallet-pin b is exerted at the instant when it will produce the greatest effect.

The difference in the operations of the straight and curved impulse-faces is illustrated in Figs. 2 and 3, in each of which the radial lines, numbered, respectively, 1 2, 3, 4, and 5, at their points of intersection with the impulse-face a, divide the circumferential motion of said face into four equal parts, while the spaces between the are lines, numbered, respectively, 6, 7, 8, 9, and 10, each of which intersects one of said radial lines at the intersection of the latter with said impulse-face, represent the amount of lift given to a palletpin, 1), while passing over each oneiourth of said impulse-face.

In Fig. 3, in which is shown the ordinary straight impulse-face, a, it will be seen that the lift of the pallet-pin is nearly uniform from the commencement to the close of its contact with said face, while in Fig. 2, wherein is shown the curved impulse-face, the lift is but slight for the first quarter, is nearly twice as much for the second quarter, is three times as much for the third quarter, and five times as much for the fourth quarter.

Having thus described our invention, what we claim is 1. Au escape-wheel for time mechanism, in

which the lifting or impulse face of each tooth is formed upon arearward and outward curve, 20

substantially as and for the purpose specified. 2. An escape-wheel for time mechanism,

which is adapted to give to the pallet-pin a constantly-increasing velocity from the commencement to the close of its contact with each 2 5 GEORGE S. HEATH AMOS F. CHAMPLIN.

Witnesses:

'1. R. LAUGHTON, WALTER P. OHAMBIJRLTN. 

